[epnefrin] - hormone important to the body's metabolism, also known
as adrenaline. Epinephrine, a catecholamine,
together with norepinephrine, is secreted principally by the medulla
of the adrenal gland. Heightened secretion caused perhaps by fear or
anger, will result in increased heart rate and the hydrolysis of glycogen
to glucose. This reaction, often called the "fight or flight response,
prepares the body for strenuous activity.
The hormone was first extracted (1901) from the
adrenal glands of animals by Jokichi Takamine; it was synthesized (1904)
by Friedrich Stolz.
Epinephrine is used medicinally as a stimulant
in cardiac arrest, as a vasoconstrictor in shock, as a bronchodilator
and antispasmodic in bronchial asthma, and to lower intra-ocular pressure
in the treatment of glaucoma.